All I got to say is WTF, Some serious miss leading posts going here. Savage vs Rem two different actions.
.223 action to "shortened" .378wby that's a good one. Sounds expensive for a WSSM with a belt
I've opened feed rails on rems before it ain't rocket science, and the bolt face to .473 is no problem with an aftermarket extractor if that's what u want.
Hopefully that wasn't a jab at the possibility of running a savage head on a rem bolt.......cause there's a lot of them out there.